Ignitor burner of dual fuel flow design utilizing an eddy plate

ABSTRACT

1,030,076. Pilot burners. COMBUSTION ENGINEERING CO. Nov. 19, 1964 [Dec. 30, 1963], No. 47252/64. Heading F4T. A pilot burner comprises second and third concentric gas pipes 20, 22 disposed in an air housing first pipe or 18, an eddy plate 26 supported by the gas pipes 20, 22, and a sparking plug 36 supported from the eddy plate 26, a stable flame being formed in the lee of the plate 26 at openings 28 in the gas pipe 20 to maintain a pilot flame partially formed by combustion of gas discharged from openings 32 in a flattened end of the gas pipe 22. An intermediate flame is formed at openings 34 in the gas pipe 20 to link the stable flame with the pilot flame, and the pilot flame is also partially formed by gas discharged from openings 30 in a flattened end of the gas pipe 20. A pilot burner, Fig. 1 (not shown), is associated with a main burner 14, burning pulverized coal or bunker C oil, mounted in each corner of a furnace 8 of a steam generator, which is of square section in plan and which is lined with steam-generating tubes 12 on all four walls. The pipes 20, 22 are provided with independent manually or automatically controlled valves 38, 40. Pressure tubes 44, 42 are connected to opposite sides of a diaphragm 48 to which is attached a switch which energizes a circuit 52 when a flame exists to actuate an indicating light 54 and/or a valve 56 controlling fuel flow to the main burner 14.

NOV. 15, 1966 HARTLINE 3,285,319

IGNITOR BURNER OF DUAL FUEL FLOW DESIGN UTILIZING AN EDDY PLATE Filed Dec. 30 1963 5 Sheets-Sheet 1 FIG.

INVENTOR, R. ACTON HARTL l/VE W .t 01km ATTORNEY Filed Dec. 30, 1963 Nov. 15, 1966 R. A. HARTLINE 3,285,319

IGNITOR BURNER OF DUAL FUEL FLOW DESIGN UTILIZING AN EDDY PLATE 5 Sheets-Sheet 2 INVENTOR. R. ACTON HARTL/NE BY W; 0124) ATTORNEY 3,285,319 EDDY PLATE R. A- HARTLINE Nov. 15, 1966 5 Sheets-Sheet 3 Filed Dec. 30 1963 INVENTOR.

R. ACTON HARTL/NE BY W cf ATTORNEY 8 0 5 in. 02 a px; w M n 2 3 o 8 O 2 United States Patent 3,285,319 IGNITOR BURNER 0F DUAL FUEL FLOW DESIGN UTILIZING AN EDDY PLATE R. Acton Hartline, Thompsonville, Conn., assignor to Combustion Engineering, Inc., Windsor, C0nn., a corporation of Delaware Filed Dec. 30, 1963, Ser. No. 334,512 Claims. (Cl. 158-115) This invention relates to a fuel burner and in particular to an ignitor or pilot burner capable of maintaining a large, stable flame.

It is an object of this invention to provide a pilot burner which has a stable flame by providing an intimate mixing of the fuel and air therein.

It is a further object to provide a pilot burner having a high B.t.u. firing rate, so that a large flame can be maintained for reliable ignition of hard to ignite main burner fuels, such as pulverized coal or bunker C oil.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a cross sectional plan view of a furnace incorporating the novel burner arrangement;

FIGURE 2 is an enlarged cross sectional view of the ignitor burner taken on line 2-2 of FIG. 1;

FIGURE 3 is a view of a portion of the ignitor burner taken on line 33 of FIG. 2;

FIGURE 4 is a sectional view of the burner tip shown in FIGURE 2.

Looking now to FIG. 1 of the drawings, numeral 8 designates the furnace of a steam generator, all four walls 10 of which are lined with steam generating tubes 12. Mounted in each corner of the furnace 8 is a main burner 14, to which fuel and air are supplied. In order to ignite the fuel and air issuing from the main burners, each main burner 14 has an associated ignitor or pilot burner 16. These ignitor burners are utilized in establishing flame at the main burners when initially starting up the unit and also for stabilizing the main burner flame, when the steam generator is operating at low l-oads( when minimum amounts of fuel are being fired in the main burners).

FIGURES 2 and 3 are enlarged views of the ignitor burner shown in FIGURE 1. Each burner 16 has an outer housing or pipe 18 which is supplied with air through duct 19. Positioned within ipe 18 are a pair of concentric fuel pipes 20 and 22 which are supplied with gas.

Positioned within housing or pipe 18 is an eddy plate 26. As best seen in FIG. 2, a restricted opening is thus formed between the periphery of the eddy plate 26 and the inner wall of pipe 18, through which all of the air flows past the eddy plate in a hollow cylindrical shape or pattern. Because of the restricted annular space between the eddy plate and pipe 18, eddy currents of air are formed, as shown in FIG. 2, which brings a small amount of air back adjacent to the downstream face of the eddy plate. This air mixes with the gas issuing from openings 28, which are positioned equidistantly around the periphery of pipe 20. The combustible mixture is ignited by spark plug 36. Since this flame is protected from the high velocity air flow by eddy plate 26, it is a very stable flame, regardless of how much fuel and air is being supplied to the burner.

Fuel pipe 20 also has a plurality of openings 30 at its end, as best seen in FIGURES 3 and 4. Inner pipe 22 also has a plurality of openings 32. Thus the flame established adjacent the eddy plate ignites the fuel flowing through openings 30 and 32. This fuel discharged through openings 30 and 32 burns in the form of a long flame which extends well into the interior of the furnace,

as shown in FIG. 1, thus forming a large stable ignition flame for the fuel and air coming from the main burner.

A number of openings 34 are formed in fuel pipe 20 approximately midway between openings 28 and 30. The fuel flowing through these openings prevents :a flame void from being created between openings 28, and 30, 32. Thus a continuous, uninterrupted flame is maintained which extends from the eddy plate to the openings 30, 32. In most burners, the size of the openings 34 can be smaller than openings 28 and 30 since only a relatively small amount of flame is needed at this point to insure a continuous flame reaching to openings 30 and 32.

By reason of the manner in which the fuel and air are introduced into the ignitor burner, it is possible to burn 5-10 million B.t.u.s per hour in an ignitor burner constructed in accordance with the invention, while maintaining a completely stable flame under all operating conditions. This is considerably more than the maximum capacity of most ignitors burners presently in use today.

In order to obtain the optimum distribution of fuel in the ignitor burner, pipes 20 and 22 are provided with control valves 38 and 40, respectively. Thus, the flow of fuel to each fuel pipe 20 and 22 can be separately and independently controlled. These valves 38 and 40 can be either manually or automatically controlled, as desired.

Apparatus 46 is a flame detector, which indicates whether or not a flame is present in the ignitor burner. The pressures existing at a point adjacent eddy plate 26 and a point further downstream thereof, are transmitted to opposite sides of diaphragm 48 by means of pressure taps 44 and 42. The pressure differential between these points is greater when a flame exists than when no flame exists. A stem containing a switch thereon is attached to the diaphragm 48. This switch can be so positioned that it energizes the electrical circuit 52 when a flame exists, thus actuating an indicating light 54 and/or a value 56.

As shown in FIGS. 2 and 3, legs 58 support the eddy plate 26 and associated fuel pipes, thus maintaining proper position of the eddy plate with respect to pipe 18.

The eddy plate is positioned back a few feet from the furnace interior, so that the spark plug 36 is not detrimentally affected by heat radiation from the furnace.

In operation, air is supplied to pipe 18 from duct 19. The spark plug 36 is energized and then fuel is supplied to pipes 20 and 22. As soon as flame has been established in an ignitor burner, fuel and air can be supplied to its associated main burner, which is ignited by the ignitor burner flame.

While I have shown and described the preferred embodiment of the invention, it is to be understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

What I claim is:

1. In an ignitor burner where a combustion supporting medium and fuel are burned, a first. pipe having an inlet end, to which a combustion supporting medium is supplied and an outlet end for discharging products of combustion, an eddy plate positioned within said first pipe, there being a restricted annular space between said eddy plate and the first pipe, a second pipe, to which fuel is supplied, positioned within said first pipe and extending through the eddy plate, said second pipe having an outlet positioned within said first pipe downstream of and adjacent to said eddy plate, ignition means positioned downstream of said eddy plate for igniting the fuel and combustion supporting medium adjacent the eddy plate, a third pipe, to which fuel is supplied, positioned within said second pipe, said third pipe having an outlet downstream of the outlet of said second pipe, whereby a portion of the combustion supporting medium combines with the fuel being emitted through the outlet of the second pipe to establish a stable flame, and the remaining portion of the combustion supporting medium combines with the fuel being emitted through the outlet of the third pipe, the flame issuing from the second pipe maintaining combustion of the fuel discharged from the third pipe, first flow control means positioned in said second pipe and second flow control means positioned in said third pipe, whereby the amount of fuel being discharged from the outlets of the sec-nd and third pipes can be separately and independently regulated.

2. In an ignitor burner where air and fuel are burned, a first pipe having an inlet end to which air is supplied and an outlet end for discharging products of combustion, an eddy plate positioned Within said first pipe in such a manner that there is a restricted annular space between said eddy plate and the first pipe, a second pipe to which fuel is supplied positioned within said first pipe and extending through the eddy plate, said second pipe having a first outlet positioned within said first pipe downstream of and adjacent to said eddy plate, a third pipe to which fuel is supplied, positioned within said second pipe, said third pipe having an outlet downstream of the first outlet of said second pipe, said second pipe having a second outlet intermediate the first outlet of the second pipe and the outlet of the third pipe, the air to support combustion of all of the fuel being supplied through the first pipe, whereby a very stable flame is established in the ignitor burner, including first valve means positioned in the second pipe and second valve means positioned in said third pipe, whereby the amount of fuel supplied to said second and third pipes can be separately and independently controlled.

3. The ignitor burner set forth in claim 1, wherein said second pipe surrounds said third pipe.

4. The igni-tor burner set forth in claim 1, wherein said second pipe and said third pipe are concentric.

5. The ignito-r burner set forth in claim 1, including ignition means poi-s'tioned within said first pipe downstream of and adjacent to said eddy plate for igniting the fuel issuing from the outlet of said second pipe.

References Cited by the Examiner UNITED STATES PATENTS 1,966,054 7/1934 Wheeler 122235 3,117,619 1/1964 Lange et al. 158-115 3,123,027 3/1964 Livingston -28 JAMES W. WESTHAVER, Primary Examiner.

FREDERICK L. MATTESON, IR., Examiner.

H. B. RAMEY, Assistant Examiner. 

1. IN AN IGNITOR BURNER WHERE A COMBUSTION SUPPORTING MEDIUM AND FUEL ARE BURNED, A FIRST PIPE HAVING AN INLET END, TO WHICH A COMBUSTION SUPPORTING MEDIUM IS SUPPLIED AND AN OUTLET END FOR DISCHARGING PRODUCTS OF COMBUSTION, AN EDDY PLATE POSITIONED WITHIN SAID FIRST PIPE, THERE BEING A RESTRICTED ANNULAR SPACE BETWEEN SAID EDDY PLATE AND THE FIRST PIPE, A SECOND PIPE, TO WHICH FUEL IS SUPPLIED, POSITIONED WITHIN SAID FIRST PIPE AND EXTENDING THROUGH THE EDDY PLATE, SAID SECOND PIPE HAVING AN OUTLET POSITIONED WITHIN SAID FIRST PIPE DOWNSTREAM OF AND ADJACENT TO SAID EDDY PLATE, IGNITION MEANS POSITIONED DOWNSTREAM OF SAID EDDY PLATE FOR IGNITING THE FUEL AND COMBUSTION SUPPORTING MEDIUM ADJACENT THE EDDY PLATE, A THIRD PIPE, SAID THIRD PIPE HAVING AN OUTLET DOWNSTREAM SECOND PIPE, SAID THIRD PIPE HAVING AN OUTLET DOWNSTREAM OF THE OUTLET OF SAID SECOND PIPE, WHEREBY A PORTION OF THE COMBUSTION SUPPORTING MEDIUM COMBINES WITH THE FUEL BEING EMITTED THROUGH THE OUTLET OF THE SECOND PIPE TO ESTABLISH A STABLE FLAME, AND THE REMAINING PORTION OF THE COMBUSTION SUPPORTING MEDIUM COMBINES WITH THE FUEL BEING EMITTED THROUGH THE OUTLET OF THE THIRD PIPE, THE FLAME ISSUING FROM THE SECOND PIPE MAINTAINING COMBUSTION OF THE FUEL DISCHARGED FROM THE THIRD PIPE, FIRST FLOW CONTROL MEANS POSITIONED IN SAID SECOND PIPE AND SECOND FLOW CONTROL MEANS POSITIONED IN SAID THIRD PIPE, WHEREBY THE AMOUNT OF FUEL BEING DISCHARGED FROM THE OUTLETS OF THE SECOND OF THE THIRD PIPES CAN BE SEPARATELY AND INDEPENDENTLY REGULATED. 